In the following article it states space may not be grainy. I guess my question is this. Haven't phycisist already ruled out graininess already less than 10^-35 meters. Isn't this nothing new?
Established Member
In the following article it states space may not be grainy. I guess my question is this. Haven't phycisist already ruled out graininess already less than 10^-35 meters. Isn't this nothing new?
Order of Kilopi
Which article?
This one? http://www.nature.com/news/cosmic-ra...n-a-tie-1.9768
Established Member
Yeah, good work!Originally Posted by Strange
Established Member
You are correct. And IIRC, the limit on time increments is well below the Planc interval. The Intelligent Designer had three martinis, sat down at his drawing board, and said 'Smooth, really smooooth.'
I'm not a hardnosed mainstreamer; I just like the observations, theories, predictions, and results to match.
"Mainstream isn’t a faith system. It is a verified body of work that must be taken into account if you wish to add to that body of work, or if you want to change the conclusions of that body of work." - korjik
Established Member
i miswrote, i meant Haven't physcisist already ruled out graininess of "greater" than 10^-35 meters.
http://www.msnbc.msn.com/id/48863290...tical-physics/
Administrator
It should be noted that 10-35 meters is still way larger than infinitesimal.
It should also be noted that the tests of graininess make some assumptions about the behavior of matter and energy as they pass from group of grains to group of grains (if there are grains)... so at best you can say some variations on some models have been ruled out.
Forming opinions as we speak
Established Member
Agreed! Although 10-35 meters seems tiny, it is not infinitesimal.
Banned
It's a clever experiment, but based on wrong presuppositions.
You see, about only 4.3-4.6% or so of the universe is made up of the stuff we recognize in daily life. If the experiment is basing the smoothness of spacetime by measuring the photons, then clearly the experiment is not accurate, since photons do not interact with either the dark energy or dark matter particles. If you try and dilute only 4% of all matter which does interact with it on universal scales, it should be no wonder photons appear to move in an almost non-grainy vacuum.
13 billion years ago, dark matter dominated. It covered over 60% of all the matter in the universe. Today, dark energy dominates, covering over 70% of all the energy in the universe. Neither of these massive chunks of the materials in the universe would effect a photons trajectory.
Administrator
You should read the article. It isn't talking about the smoothness of matter, or dark matter, or dark energy. This is a question about the scale and/or existence of Heisenberg foam.
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Banned
Well, it says
'' In a simplified explanation, photons with the highest energies have wavelengths comparable to the Planck length, so are more likely to interact with and be slowed down by these 'lumps'. Although the slowing effect is minuscule, the difference is amplified as the particles journey for billions of years across the vast distances of the cosmos.''
To me this is questioning how smoothly a photon will move through matter. For billions of years, my point being, is that a photon doesn't even interact with most of the matter in the universe. Most of the matter, does not interact electromagnetically, so of course it will smoothly move through it. Spacetime can still be grainy in the presence of this stuff we don't detect.
Administrator
You are misunderstanding it. I don't have time to try and figure out where you went wrong, but it isn't talking about matter.
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Banned
The smoothness of spacetime is due to how flakey quantum fluctuations make it. All kinds of matter and energy are fluctuations. The vacuum is basically, quantum fluctuations.
Exactly, where do you think I have gone wrong?
Banned
I believe you have misunderstood the article. The article is talking about the graininess, or quantum makeup of the vacuum. The vacuum is made up of fluctuations which is what we call matter. I am explaining that photons only interact with a mere 4% of all matter in the universe, so no wonder their experiment turned up a near smooth vacuum.
Established Member
Nope. The flucutations can be bosonic too. Unless you call photons matter too?The vacuum is made up of fluctuations which is what we call matter.
Banned
I refer you to post 36. I clearly note matter and energy are fluctuations. My reply was to Anton who states this is not talking about matter. However, both matter particles and energy particles make up quantum fluctuations.
Banned
http://faculty.washington.edu/smcohe...ainySpace.html
A good reference to show what I am talking about.
Banned
Also, how do you distinctly identify bosons with zero mass, may I ask?
Some Bosons have a mass... you know?
Established Member
Of course the minor issue is that quantum fluctuations are not the same as quantum graininess...
Banned
Well actually, the graininess of spacetime are fluctuations which are quantum particles.
Banned
You cannot separate the idea of quantum fluctuations and particles, which my link hints at as well.
Banned
what do you think it is?
From the article
''In the 1950's, the physicist John Wheeler suggested that the Planck length marked the boundary where the random roil of quantum mechanics scrambled space and time so violently that ordinary notions of measurement stopped making sense. He called the result "quantum foam."
Well, we all know what quantum foam is. It is the presence of quantum fluctuations at very very small levels.
edit/
Spacetime is not just a sheet. It is a violent activity of particles which gives rise to a graininess of the vacuum. This graininess is what we might associate a photon travelling through, however, as I have pointed out a few times now, a photon is only effected by 4% of all the matter in spacetime. The experiment is flawed in the OP, or at least, the assumptions brought forth.
Established Member
You seem to have a great deal of knowledge about something that has not been detected. Surely all what follows is ATM ?
Banned
Is dark energy and dark matter a matter itself of ATM?
I will leave that to those who run the site on cosmology itself. Keep in mind, dark matter and dark energy are not ATM concepts.
Administrator
I believe that your statements about matter and quantum fluctuations is what Headrush was saying were unknown and unobserved, and hence all that follow must be ATM. Dark Matter and Dark Energy are fine topics until you say we know something about them that we don't know.
Forming opinions as we speak
Banned
Not at all. Quantum foam is not ATM, it has been observed.
Have you heard of the Casimir Effect?
Order of Kilopi
And this is where you are wrong. It's questioning how a photon will move through space-time. The lumps are lumps (or the graininess) of space-time, not matter. Nor are they lumps of energy. Unless, of course, you are equating the lumpiness of space-time with energy particles, are you? The article, is talking about Lorentz Invariance. At the scale the article (and the referenced papers) are talking about, high energy Gamma Rays will not travel at c because space-time will not be isotropic nor homogeneous, IOW, not Lorentz invariant. Of course, the experiments to date have not found any verifiable differences in the speed of high energy gamma rays, all they have done is constrained the size of the grains (or lumps) of space-time.
Order of Kilopi
The Casimir effect has nothing to do with Quantum Foam and everything to do with Quantum Electrodynamics and charges and currents. You do not need a reference to zero point energies to compute the Casimir effect. See here
Banned
Am I just speaking to myself?
You do realize that the graininess of spacetime is due to quantum foam... right? You do know what quantum foam is... right?
Space and time is a sheet with what are called distortions. This is what causes the graininess.
Banned
So wrong it is beyond belief.
Quantum foam are quantum fluctuations. The Casimir Effect is due to quantum fluctuations.
Banned
You can check any good website for this information. The Casimir effect is due to quantum fluctuations. They are due to particles within the sheet of the vacuum. The vacuum is not a case of empty space, it is filled with virtual particles and antiparticles. Our normal everyday matter, interacts with a small proportion of this stuff.
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